Online Exclusive

Cranes Play Major Role in Iowa Wind Farm Construction

Once completed, the Rolling Hills Wind Project in Massena, IA, will be one of the nation's largest wind farms. Site preparation for the project began in April 2011, and turbine erection should complete by November. When finished, the turbines will produce enough electricity to power approximately 190,000 homes.

Mortenson Construction is the general contractor for project owner MidAmerican Energy. As part of a larger project, Mortenson will also be working on two additional wind farms: the Laurel and the Pomeroy IV. The three farms together will span more than 150 square miles across six counties.

Helping to erect 193 wind turbines on the the Rolling Hills Wind Project are three Manitowoc 16000 crawler cranes with wind attachments, two 14000s, two 888s and two 2250s, plus several Grove rough-terrain cranes. The crawlers were rented from Dawes Crane and Laramie Cranes.

Steven Klatt, crane manager for Mortenson, said the company chose the cranes because they could work together efficiently on the large project.

"The Manitowoc 16000s with the wind attachments are what we consider our main erection cranes," said Klatt. "They have the capacity and reach for the heaviest and highest picks. The 2250s are our base cranes, and the 888s and 14000s are being used to build the rotors. During turbine erection, the Grove RTs are used for tailing as well as off-loading components from trucks."

The Manitowoc 16000 has a maximum capacity of 440 USt and a maximum reach of 432 ft. To place the turbines on the 80 m towers, they have been configured with 301.8 ft. of main boom and 24.9 ft. of upper boom with the wind attachment. The wind attachment is designed to increase the reach and capacity of the crane at short radii, which is especially beneficial in wind turbine erection. At a 59-ft. radius, the wind attachment yields a capacity advantage of 49% over a standard 16000.